222 Reports and Proceedings. 



present in nearly all those examined, and, with one exception, was 

 of the white variety ; 5th, Soluble silicates were only found in three 

 varieties, in any quantity, all three belonging to the Old Eed Sand- 

 stone ; 6th, That the different shades of colour seen in those sand- 

 stones belonging to the last-mentioned rocks appeared to be due 

 solely to the peroxide of iron, and that the white rings and spots so 

 often observed have resulted from the reduction and subsequent 

 removal of the greater part of this iron. 



Dr. Young concluded his remarks on the Osteology of Fishes on 

 which he had previously lectured (14th March.) In that lecture he 

 pointed out the arrangement of the facial bones in the osseous and 

 Ganoid orders among living fishes, and indicated their homologues, 

 so far as they had been established, in the higher vertebrates. He 

 then described the structure of the head of Megalichthys, and, compar- 

 ing it with that of Polypterus and Amia (two living ganoids found in 

 Egypt and the Southern States of America), he explained the close 

 connection which had been established between the former living 

 genus and the extinct family in which MegalicMliys is included. On 

 the present occasion he briefly summed up the grounds on which 

 Falceoniscus and the majority of Mesozoic fishes are included in the 

 same family with Lepidosteus, the North American ganoid, and 

 referred to the new genus CalamoicJitJiys, of J. A. Smith, as repre- 

 senting, in the absence of the ventral fin, Platysomus and its allies. 

 He then showed that the progression which had been asserted as 

 observable among fish from Paleeozoic to modern times was not sup- 

 ported by the facts, since there was reason to believe that osseous 

 fishes existed in the Old Eed Sandstone, and, in the structures just 

 described, presented as high a stage of development in ancient as in 

 recent times. He then discussed the forms of the caudal fin, and, 

 illustrating this subject from the researches of Kolliker, Huxley, and 

 others, showed that " homocercal " was a term liable to create confu- 

 sion, since the majority of osseous fishes are as " heterocercal " as 

 the sharks. The unequal division of the tail presents several degrees 

 both in extinct and living ganoids, which might be described as 

 "heterocercal equilobate, or inequilobate." " Diphy cereal," M'Coy's 

 term, should be restricted to truly homocercal tails, as of Coelacanthus 

 and Bijplopterus. The difficulties of classifying fishes were spoken of 

 in reference to the arrangement according to scales, as proposed by 

 Agassiz ; and the true principle, that of grouping according to the 

 sum of characters explained. — J.A. 



MoNTKEAL Natural History Society. — The first lecture of the 

 Somerville course for the present season was delivered on Thursday 

 evening, January 17th, by Dr. P. P. Carpenter, who chose for his 

 subject, " The works and ways of shell-fish." 



11. — On January 26th, the President (Dr. Hunt) in the chair. 

 Principal Dawson then read a paper " On certain discoveries in 

 regard to JEozoon Canaclense." 



The paper was preceded by one from Mr. H. Gr. Vennor (of the 



